1. Field of the Invention
The present invention relates to a reactive ion etching apparatus with a wafer transferring mechanism which is used for manufacturing semiconductor devices.
2Discussion of Background
FIG. 2 shows a conventional reactive ion etching apparatus disclosed, for instance, in a catalogue of "R-206A model piece-by-piece treatment type dry-etching apparatus" manufactured by HITACHI LTD.
In FIG. 2, a wafer 1 is received in each cassette 2,3. An etching apparatus 100 and an after treatment apparatus 200 respectively contain reactive chambers 101 and 201. The etching apparatus 100 and the after treatment apparatus 200 have the same wafer-transferring mechanism although they have different structure of electrodes. The etching apparatus 100 is provided with a first load lock chamber 102 for introducing the wafer, a second load lock chamber 103 for drawing out the wafer, a wafer transferring belt 104, a lateral-transferring belt 105, a drawing-out belt 106, a stage 107, a pair of transfer arms 108, 109, gate shutters 110-112 for opening and closing passages of the wafer 1, a first reactive chamber 101 and a buffer room 113. The after treatment apparatus 200 is also provided with a first load lock chamber 202 for transferring the wafer, a second load lock chamber 203, a wafer transferring belt 204, a lateral-transferring belt 205, a drawing-out belt 206, a stage 207, a pair of transfer arms 208, 209 for transferring the wafer, gate shutters 210-211 for opening and closing the passages of the wafer 1, a second reactive chamber 201 and a buffer room 213.
In the conventional ion etching apparatus having the above-mentioned construction, operations for etching the wafer followed by an after treatment have been conducted as follows.
The wafer 1 is put in the cassette 2 and the pressure of the load lock chamber 102 is reduced to the same extent of a pressure in the buffer room 113. The gate shutter 110 is opened and the cassette 2 carrying the wafer 1 is forwarded into the buffer room 113 by means of the wafer transferring belt 104. Then, the cassette 2 is laterally moved to be put on the stage 107 by means of the lateral-feeding belt 105 which is perpendicular to the wafer transferring belt 104. The wafer 1 is subjected to posture adjustment such as flatness and orientation on the stage 107 although the mechanism of the posture adjustment is omitted. Then, the wafer 1 is forwarded to the first reactive chamber 101 by means of the transfer arm 108.
After completion of an etching treatment in the reactive chamber 101, the wafer 1 is returned to the stage 107 by the transfer arm 109. After the gate shutter 112 is opened, the wafer is forwarded to the stage 207 through the lateral-feeding belts 105, 205. The gate shutter 112 is then closed, and the transfer arm 208 transfers the wafer 101 to the second reactive chamber 201, where the after treatment is carried out. After the treatment is finished, the wafer 1 is returned to the stage 207 by the transfer arm 209. Pressure in the load lock chamber 203 is reduced to the same extent of the buffer room 213. The gate shutter 211 is opened and the wafer 1 is forwarded to the load lock chamber 203 through the lateral-feeding belt 205 and the wafer transferring belt 206 to be put on the cassette 3.
The operations of the etching and the after treatment for a second wafer 1 may be started before the above-mentioned operations for the first wafer 1 are finished.
As described above, the conventional reactive ion etching apparatus is advantageous in that standardization of the apparatus is possible because the same mechanism can be applied to the etching apparatus and the after treatment apparatus, and these apparatuses can be used as a single unit by connecting them in series. However, when the etching apparatus and the after treatment apparatus have to be connected in series, there arise problems that the whole unit becomes expensive, occupies much space and increases the number of operations such as opening of the gate shutter 112.